Showerhead reactors are used for chemical vapor deposition and plasma etching in semiconductor processing. Many are a type of chemical vapor deposition reactor known as “cold wall” reactors. Walls of the reactor chamber, the showerhead which dispenses gases, and the chamber body are kept relatively cool (e.g. at ambient temperature or slightly above) in order to discourage outgassing from or chemical reactions on these components of the reactor. On the other hand, a semiconductor wafer, susceptor holding a thin-film, or other substrate or work piece (a.k.a. “workpiece”) are heated inside the reactor as by a heated chuck or the like, in order to facilitate chemical vapor deposition reactions or etching at the work piece. When a work piece is moved within the reactor, such as for further processing or testing, the work piece can cool and deposition reactions will not be optimal.
When a semiconductor wafer, susceptor, substrate or other work piece is transferred from one showerhead reactor to a further showerhead reactor, such as for tandem sequential processing of the work piece, the work piece often cools somewhat and experiences a thermal dip. The work piece is then heated or reheated to a desired temperature in the further showerhead reactor and processing of the work piece continues. However, the thermal dip introduces undesirable effects. There can be a reduction in temperature uniformity of the wafer due to differential cooling. A reheated work piece with residual temperature variations can experience uneven deposition, particulate contamination, or uneven etching in the reactor. Semiconductor wafers can undergo a “potato chip” warpage. A thin-film being grown on a reusable susceptor can lift partially from or slip on the susceptor. It is an object of the invention to provide improved temperature uniformity of a work piece being transferred from one reactor to another reactor or from one modular section of a reactor to another modular section of a reactor.